Rolled tube



y 5, 1959 L. J. ASSEL1N, sR 2,884,958

ROLLED TUBE Filed May 18, 1956 Ti I 32 f INVENTOR.

I17. 34 51/430 .1. 45:5 .0! SR.

Arr-Myer nited States Patent "ice 884358 ROLLED TUBE Leonard J. Asselin, Sr., Detroit, Mich. Application May 18, 1956, Serial No. 585,731 2 Claims. (Cl. 138-74) This invention relates to a rolled tube, and more particularly to fill the existing need for a high quality tube from the method herein improved over present manufacturing methods.

It is the object of the present invention to provide a tube construction formed from an elongated rectangular blank, rolled into cylindrical form and with the meeting longitudinal edges of the tube arranged in overlapped tapered relation and suitably bonded together.

It is the further object of the present invention to form a tube having overlapping tapered marginal edges suitably bonded together and including cooperating interlocking projections and recesses for further securing said marginal portions together.

It is the further object of the present invention to improve upon the present butt or fusion type of welds and wherein the overlapping registering edges of the rolled stock are brazed together over an area 2 to 3 times the area of the right-sectional area of the material.

These and other objects will be seen from the following specification and claims in conjunction with the appended drawing in which:

Fig. 1 is a fragmentary cross-section of a strip of basic metal.

Fig. 2 is a similar view after the initial forming step of rolling.

Fig. 3 is a similar view showing an intermediate step in forming the basic metal into a tube.

Fig. 4 is an end elevational view of the completed tube.

Fig. 5 is a cross section of strip of basic metal to be formed in a different fashion.

Fig. 6 is a cross sectional view indicating the initially bevelled portions and the formation of slots and projections.

Fig. 7 is a fragmentary elevational section illustrating an intermediate tube forming step.

Fig. 8 is an end elevational view of the completed tube.

Fig. 9 is a fragmentary elevational section of still another strip of basic metal initially formed.

Fig. 10 is a similar view of a subsequent rolling step.

Fig. 11 is an elevational section and still another intermediate step in the tube forming portion.

Fig. 12 is an end elevational view of the completed tube.

It will be understood that the above drawing indicates merely several preferred embodiments of the invention and that other embodiments are contemplated Within the scope of the claims hereafter set forth.

Referring to Figures 1 through 4 one form of tube construction is shown wherein the initial strip of basic metal 11 is shown in cross section and may be either steel, copper, brass, bronze, stainless steel, Monel, nickel, titanium, or the like.

In Fig. 2 the cross sectional shape of the strip has been changed by the action of one or two sets of vertical Patented May 5, 1959 2 rolls and some side rolls to thereby produce the flattened marginal portions 12 and 13. Furthermore, the marginal edges of the flattened portions are tapered at 14 and 15. Similarly the inner portions of the body of the strip at the inner ends of the flattenedportions are provided with additional projecting portions 16 and 17.

In Fig. 3 the stock is shown in an intermediate stage as it begins to assume an arcuate shape.

In Fig. 4 the tube is shown completed with the flattened portions 12 and 13 arranged in overlapped relation and with their respective tapered edges 14 and 15 cooperatively interlocked with the corresponding tapered portions 16' and 17', formed from projections 16 and 17.

The said overlappingedges and the interlocked portions are suitably bonded together in any one of a number of ways. This may be accomplished by covering either the entire strip surface or only that portion of the strip if necessary with a suflicient bonding material to insure a solid homogeneous alloying of the basic metal with the bonding metal as indicated at B Fig. 4.

The bonding metal may be a plating, a rolled on metal, a hot dipped coating, or a bonding material may be furnished by running a basic metal formed tube through a molten bath of the desired bonding metal for example; with a steel tube, a bonding material may be of copper, bronze, brass, tin or lead, for illustration.

The present tube will be easily and safely formed, bent, flattened, swaged, extended or otherwise deformed after bonding in a conventional manner.

The present tube is much rnore economical to produce, as the present strip used will not require an excess amount of cold rolling at the steel supplier and will not necessarily require plating, which is expensi e.

The quality of the present tube will be better than that produced by the common butt or fusion electric weld or the wire-fed type which leaves occasional voids.

In the American Society of Metals Handbook 1948 edition, page 79, first column in an article entitled Preparation and Design of the Joint, third paragraph:

When the full strength of sheet metal, or of round or rectangular bars or wires is to be developed by means of a braze in shear, or partly in shear and partly in tension, a common rule is to make the brazed area 2 to 3 times the area of the right section of the base metal.

This shows the advantage of the beveled joint of the present invention over the butt joint inasmuch as for a given angle of bevel a definite area of shear, dependent on the strip thickness will always be available.

The angle may be so chosen that the shear area may be 2 to 3 times the right section area.

An additional advantage resides in the present construction in that metal when cold rolled has a tendency to spring-back when the working force is removed. Referring to Fig. 4 the more this spring-back force exerts its pressure the tighter the joint will be. This insures close contact of the registering portions when the tubing is subjected to heat and produces a high quality bond.

In completing the tube from the illustration of Figures 3 and 4 there are involved well known working procedures. 7

In the present preferred embodiment the strip 11, i.e. the elements 12 and 13 are flattened for a length of approximately or at least 20 percent of the tube circumference. This is not by way of limitation inasmuch as the flattened length may vary dependent upon various factors, such as the tube outside diameter and wall thickness. Accordingly the portions of reduced thickness, i.e., the overlapped elements 12 and 13 may approach any desired percentage of the circumference towards a complete double wrap, but never quite doing so.

In the preferred embodiment the bond may be accomplished by brazing or welding B and for illustration could take place in an electric or gas fired furnace, or could be produced by high frequency or resistance welding.

The purpose of the heating is to bring the bonding material up to a temperature to cause same to melt and diffuse into the basic metal, forming an alloy which will have a higher melting point than the original bonding material, and thus produce a truly bonded tube. Thereafter, the tube is completed by passing through a cooling section or apparatus.

In the case of steel as the body of the tube, the bonding material may be copper, bronze, or other lower melting point material. The melting and bonding preferably takes place in a hydrogen or reducing atmosphere in an electric furnace or other furnace.

After cooling the tube may be cut to the desired lengths, formed, bent or put through any desired fabrication.

It is contemplated in the case of steel tube that a terne or tin coating may be applied by hot dipping in a customary manner to increase corrosion resistance of the steel tube.

When the present method is utilized in making copper tubing, the cost thereof will be cheaper than that produced by conventional methods. The bonding material, such as a very low tin-bnonze, may be used to give a very high purity copper tubing 'with a negligible percentage of tin.

Other basic materials may be bonded by any metal which has a lower melting point than the basic metal of the tube and which bonding metal is known to alloy readily with the particular metal of the tube.

Referring to Figures through 8 there is shown a strip of material 18 of rectangular cross-section, Fig. 5 which is tapered by rolling upon its under surface along one marginal edge as at 19, Fig. 6. Similarly the opposite marginal edge of the strip 18 throughout its top surface is tapered as at 20, whereby when the strip is transversely rolled, Figures 7 and 8, into the tube of Fig. 8, the end surfaces of the tapered edges 19 and 20 will be arranged in snug contacting, cooperating engaging relation.

To improve upon the juncture between said registering tapered edges there are formed in the two tapered edges 19 and 20 respectively the spaced elongated projections and recesses 21 and 22.

In the final tube formation'these projections and recesses are joined together in interlocking relation, Fig. 8 and with the braze or weld B of suitable alloying material provided a very eificient tube construction.

Fig. 8-A shows a slight variation wherein the respective portions 32 of the tube have tapered contacting edges 33 and 34 and wherein a series of projections 35 are formed upon tapered edge 34 and a corresponding number of elongated spaced recesses 36 formed within the registering edge 33.

In the finally assembled tube which is also bonded as at B, the said projections and recesses are secured in interlocking relation and in cooperation with the braze or weld completing the tube construction.

Figs. 9 through 12 illustrate a slight variation in the tube construction shown in Fig. 4, as it will be noted that the interlocking tapered edges and recesses are additionally interlocked or secured together by the cooperating projections and recesses 27 and 31.

Here the strip 23 Fig. 9 is shown after several initial rolling steps which provide elongated edge portions 24 of Fig. 4 and and 25 of reduced thickness. These edges terminate in the oppositely arranged tapered margins 26 and 28, from which extend elongated projections 27.

Fig. 10 corresponds to Fig. 2 but includes the said projections 27. This figure also includes the projections 29 and 30 on opposite sides of the body of the material 2.3. In Fig. 12 elongated formed recesses 31 are formed from the projections 29 and 30. Consequently in completing the tube of Fig. 12 there are provided three different factors which effectively cooperate to complete the tube construction.

In the first place the overlapping reduced thickness edge portions are bonded together. Secondly their margins are tapered at 26 and 28 for interlocking engagement with the recesses formed from projections 29 and 30. Their engaging surfaces are also bonded in the brazing process. Additionally the interlocked tapered members have additional longitudinally extending interlocked projections and recesses.

The tube shown in Fig. 8 differs from the tube in Fig. 4 as there is provided only one bevel as at the weld B, Fig. 8, but this in addition to the brazing has the corresponding bevelled edges at 19 and 20 interlocked.

The tube of Fig. 12 incorporates the tube structure additionally the interlocking structure shown in Fig. 8.

Having described my invention reference should now be had to the claims which follow for determining the scope thereof.

I claim:

1. In a rolled tube, the body thereof including a pair of longitudinally extending edge portions of reduced thickness in snugly overlapped engaging relation throughout an appreciable portion of the tube circumference, the ends of said edge portions being tapered from one side to the other defining pointed end edges, corresponding body portions at the inner ends of said portions of reduced thickness having similarly tapered recesses cooperatively receiving said tapered end portions in interlocking relation, said tapered recesses and end portions extending continuously throughout the length of the tube body, and an alloyed braze interposed between the contacting surfaces of said overlapped and interlocked portions, there being cooperating interlocking projections and notches formed in the registering taper-ends and recesses, said projections and notches extending continuously throughout the length of the tube body.

2. In a rolled tube, the body thereof including a pair of longitudinally extending tapered edges arranged in snugly overlapped engaging relation, there being similarly shaped elongated interlocked projections and recesses formed in said tapered edges, and an alloying braze securing and bonding said contacting surfaces, said projections and recesses extending continuously throughout the length of the tube body.

References Cited in the file of this patent UNITED STATES PATENTS 755,436 Bentel Mar. 22, 1904 1,180,859 Lefever Apr. 25, 1916 1,891,740 Westerman Dec. 20, 1932 1,933,279 Quarnstrom Oct. 31, 1933 2,012,889 McIntyre Aug. 27, 1935 2,086,143 Van Hufiel July 6, 1937 2,198,415 Quarnstrom Apr. 23, 1940 2,683,927 Maronex July 20, 1954 2,756,172 Kidd July 24, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,884,958 v May 5, 1959 Leonard J. Asselin, Sr.

It is hereby certified that error. appears. in the above numbered patent requiring correction and that the said Letters Patent should read as corrected In the grant, address of patentee, for "Detroit, Michigan" read La Grange Illinois in the heading to the printed specification, line 3, for "Detroit,

Mica -read La Grange, 111-,

. Signed and sealed this: 18th day of August 1959.

' -(SEAl,)

Attest:

K R MINE ROBERT c. WATSON Attesting Officer g Conmissioner of Patents 

